Charge forming device



W. H. TEETER W Alma e 1 m J 9 .1 m M w N mm m vs M m g NNQ y/ m T S kmon w E w 8 1 x a m.. ms in m May 3, 1932.

I CHARGE FORMING DEVICE May 3, 1932. w. H; TEETER CHARGE FORMING DEVICE3 Sheets-Sheet 2 Filed Sept. 25, 1928 type.

Patented May 3, 1932 PATENT Fries;

WILFORD H. TEETER, OF DAYTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, 'IODEL-CO PRODUCTS CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARECHARGE FORMING DEVICE Application filed September 25, 1928. Serial No.308,243.

This invention relates to charge forming device for internal combustionengines, and more particularly to a charge forming device for amulti-cylinder engine, which comprises .3 a plurality of primary mixingchambers one all operating conditions and to secure equal distributionof this mixture to the various engine cylinders.

It is one object of the present invention to provide means to secure amore homogeneous mixture of fuel and air under all operating conditionsthan is formed by prior devices of this character, to secure equaldistribution and delivery of this mixture to the various engine intakeports, and to provide a device for effecting these results which issimpler in construction, easier to manufacture and cheaper than earlierdevlces of thls similar A further object of the invention is to providea device of simple construction which is effective to provide a mixtureof proper proportions during the acceleration period immediatelyfollowing an opening movement of the throttle.

According to this invention these objects are accomplished by theprovision of a plurality of mixing chambers each of which has a separatefuel nozzle and all of which are controlled by a single throttle incombination with means for separating the mixture under certainoperating conditions, at a point beyond the throttle, into its heavierand lighter constituents, and means for conveying these separate partsof the mixture through separate conduits to secondary mixing chambersiocated adjacent the engine intake ports when the separate portions ofthe mixture are reunited to be carried into the combustion chambers.

ing proper proportions of fuel and air under Further objects andadvantages of the present invention will be apparent from the followingdescription, reference being had to the accompanying drawings, wherein apreferred form of embodiment of the invention is clearly shown.

In the drawings: a

Fig. l is a plan View of the present invention attached to the cylinderhead, a part of which is shown in section.

Fig. 2 is a side elevation looking toward the engine block.

Fig. 3 is an end elevation of the carburetor unit viewed from the rightin Fig. 2.

Fig. 4 is a section on the line 4-4 of Fig. 2. Fig. 5 is a section onthe line 5-5 of Fig. 4. Fig. 6 is a section on the line 6-6 of Fig. 4.Fig. 7 is a fragmentary section on the line 77 of Fig. 4. i

Fig. 8 is a detail View showing the float valve in section.

The device disclosed herein comprises a manifold indicated in itsentirety by the reference character 10 and having three outlet passages12, 14, and 16 each of which is adapted to communicate with one of theports 18 of a multicylinder engine. Each portserves two adjacentcylinders through present valve ports 20a and 206, as clearly indicatedin Fig. 1. The cylinder head is shown in three separate fragments 22,but it will'be understood that it may be an integral structure. Thebranches 12, 14 and 16 are each provided with an attaching flange 24 forattaching the manifold to the engine block in the usual manner. Adjacentits inlet the manifold is provided with a flange 26 to which may besecured the main carburetor unit, as shown in Fig. 4.

The main carburetor unit comprises a main housing 28 in the form of asingle casting which is provided with an attaching flange 30 of the sameshape as the flange 26 and is adapted to be secured to said flange 26 by7,

screws 82. An air inlet horn 34, the flow of air through which isregulated in a manner later described, is secured in position over anopening in the upper wall of the housing 28 by screws 36 which passthrough flanges 38 and 40 on the air horn and main housing respectively.A casting 42 having certain dash pot chambers and fuel passages,described in detail hereinafter, formed therein is secured by screws 44to the lower wall of the housing 28. A sheet metal fuel bowl 46 is heldtight against an annular shoulder 48 on a skirt 49 depending from themain housing by means of a screw 50 screwed into a post 52 dependingfrom and integral with the casting 42. A gasket 54 is provided toprevent leakage around the screw.

A fuel pipe (not shown) leading to a main source of fuel supply isadapted to be connected to a. boss 56 projecting from the housing 28 andhaving a fuel channel 58 bored therein. This fuel channel communicateswith a vertical fuel channel 60 into the lower end of which a nipple 62provided with a fuel passage therethrough is secured. This nipple isprovided with lateral fuel outlets 64 through which the fuel flows intothe fuel bowl and the flow of fuel is controlled by a valve 66cooperating with a valve seat 68 in the nipple 62, the operation of thevalve being controlled by a float 7 O pivoted at 7 2 and operating inthe usual manner to maintain a substantially constant level of fuelwithin the fuel bowl.

Fuel is conducted from the fuel bowl to a plurality of primary fuelnozzles 74 projecting into mixture passages formed in the central partof the main hous ng, and indicated in their entirety by the referencenumeral 76. For convenience that part of each passage 7 6 adjacent thenozzle is termed the mixing chamber and is indicated by the referencenumeral 77. To enable the fuel to flow from the fuel bowl to the primarynozzles the casting 42is provided with a dependingtubular portion 7 8having a vertical fuel channel formed therein which connects at itsupper end with a horizontal fuel channel 82 communicating with each ofthe fuel nozzles through holes 84. Fuel is admitted to the channel 80through the metering orifice 86 which regulates the flow of fuel at allengine speeds.

Fuel is lifted from the fuel bowl through the nozzles 7 4 to the mix ngchambers by the suction maintained therein. \Vhen the throttle is movedtoward closed position to reduce the engine speed there is a suddenreduction in the suction on the vertical column of fuel between the fuelbowl and the nozzles which might permit th s column of fuel to dropsufficiently to cause a temporary fuel starving of the engine unlessmeans were provided to prevent the dropping of such column of fuel. Toprevent this action a check valve 88 is received in an enlarged chamber90 formed by the junction of the fuel channels 80 and 82 and atreduction of suction in the primary mixing chambers seats on an annularrib 83 projecting upwardly from the bottom of such chamber, preventingdownward flow through the fuel channel 80.

Each primary fuel nozzle is provided with a main fuel outlet 92 in thetop of the nozzle and a secondary fuel outlet comprising two orifices 94and 96 formed in the vertical wall of the nozzle and diametricallyopposite each other as shown in Fig. 4. At hi her speeds there issufficient suction in the primary mixing chambers to cause fuel to flowfrom the main fuel outlet in the top of each nozzle as well as from theholes 94 and 96. At idle or very low speed, however, the suction is notenough to lift the fuel through the main fuel feeding orifice, the fuelat this time standing in the nozzle at a point between the top of thenozzle and the orifices 94 and 96 and flowing from such orifices byaction of gravity. Each fuel nozzle is provided with a restricted fuelmetering orifice 98.

There are three primary mixture passages 76 which are parallel to eachother and close together as indicated in Fig. 7. The flow of mixturethrough these passages is controlled. by a single throttle valve 100journalled in the housing 28 and provided with grooves 102 whichregister with the mixture passages 76. Projecting from one end of thethrottle valve is a spindle 104 to which an operating lever 106 issecured. An operating connection is adapted to be attached to the end ofsaid arm 106 and to extend to a point convenient to the operator of thevehicle to permit manual operation of the throttle valve. end with aperipheral groove 108 which is engaged by the inner end of a set screw110 adjustable in the wall of the housing 28 to prevent any longitudinalmovement of the The throttle is provided at one throttle. At a pointimmediately posterior to the throttle valve the mixture passages 7 6 areopen at the top and communicate with a. chamber 112 formed in thehousing 28. Par titions 114 are provided in the lower part of thischamber to separate the three mixture passages, as indicated in Fig. 6.The passages 76, at their posterior ends, communicate with three smallertubular passages 118 formed in the attaching flange 30 which is adaptedto be secured to the manifold. These passages 118 communicate with threepasabove mentioned applications, and communicate with pipes 122 whichare connected at one end to the outlet ends of the passages 120 and atthe other end to elbows 124 detachably secured to the manifold branches12 and 16 in any suitable manner. These elbows communicate with tubes126 similar to the tube 121 and similarly secured in the manifoldbranches 12 and 16. Primary mixture is drawn by engine suction from themixing chambers 76 through the above described pipe connections to thesecondary mixing chambers.

Substantially all of the air entering the carburetor flows through theair horn 34, the flow therethrough being controlled by an air valve 128,normally held against a seat 130 by a compression spring 132. Air flowspast the valve into a main air cham er 134 formed in the housing 28, andfrom such chamber into the mixing chambers all of which communicate withthe air chamber 134.

When the carburetor is choked to start the engine the air valve 128 isheld against its seat to completely close the main air inlet by meanspresently described. To provide sufficient air to carry the startingfuel from the primary nozzles to the engine when the carburetor ischoked as described, an air inlet 136 is provided. This air inlet is anelongated slot formed in a plate 138 secured to the housing 28, as shownin Fig. 4c.

The air valve 128 is adjustably secured on a stem 1&0 mounted in a guidesleeve 142 fixed in the housing 28. Surrounding the guide sleeve is aslidable sleeve 14 1, the lower end of which has secured thereto a disc146 which constitutes a flange projecting outward from the sleeve H4 andprovides a seat for the lower end of the air valve spring 132. This discis adapted to be lifted to bring the upper end of sleeve 1 1% intoengagement with the underside of the air valve to hold the valve againstthe seat 130 in order to check the carburetor. The means for lifting thedisc 146 comprises an arm 148 secured to a rock shaft 150 rotatablymounted in the wall of the housing 28. The arm 1 18 is provided withtwo' pins 152 and s projecting from its inner end and the disc 1 16 isreceived between these pins. The shaft 150 projects through the wall ofthe housing and its outer end 156 is bent upwart 1y and constitutes anoperating lever for rocking the shaft. At its upper end this lever isprovided with a hole 158 in which some form of operating connectionextending from a point convenient to the operator may be attached. Anadjustable stop screw 160 is received in a lug 162 detachably secured tothe air horn as indicated in Fig. 2. By adjustment of the stop screw thenormal position of the sleeve led may be variably determined in order toregulate the tension of the spring 132. Ordinarily the stop screw isadjusted so that the air valve will be held open slightly during idling.

On opening movement of the throttle valve the suction in the air chamber134 is increased and the air valve is opened against the closing forceof its spring 132, admi ting a sur'licient quantity of air to the mixingchambers 77 to temporarily lean the mixture in the secondary carburetorssufficiently to cause improper engine operation unless means areprovided to retard the opening movement of the opening of the valve.Such means comprises a dash pot having a piston 164 secured to the lowerend of the valve stem 14:0 and a cylinder 166 in which the pistonslides, which is formed in the casting 12. To secure the piston to thestem a flanged coupling member 168 is secured to the end of the stemwhen the piston is clamped between the flange on said member and a nut170 screwed on the lower end of the member 168. The lower end of thecylinder 166 is closed by a closure member 172 having an opening 174 inthe center thereof which is closed by an upwardly opened check valve 176which permits unretarded movement of the piston, but prevents the escapeof fuel on the outward movement thereof, fuel escaping on such outwardmovement only on a leakage around the piston, thus retarding the openingmovement of the valve. This dash pot prevents fluttering of the valve aswell as leaning of the mixture.

In addition to the pipe connections previously described for conveyingthe mixture from the mixing chambers 77 to the secondary mixing chambershereinafter described, other means are provided to convey a part of themixture formed in the mixing chambers 77 to said secondary mixingchambers under certain operating conditions. This means comprises apassage 180 formed in the housing 28 and communicating with all of themixture passages 116, said passage 180 being enlarged to form thechamber 112 heretofore referred to, which extends over all of thepassages 7 6 above the partitions 114.. At its outlet end the passage180 communicates with the inlet of the manifold 10. The passage 180 isnormally closed by means of a flap valve 181 secured to a rock shaft 182pivotally mounted in the upper portion of the passage 180. The openingof this valve is normally retarded by a dash pot until the enginesuction efiective to open the valve becomes sufficient to overcome theresistance ofthe dash pot. The dash pot includes a cylinder 183 having aprojecting flange 18 1 secured by screws 185 to the main housing. Apiston 186 is slidably received within the cylinder and fits in saidcylinder tightly enough to oppose the opening of the air valve 181 tosuch degree as is desired. A light spring 187 is received in thecylinder 183 below the piston 186, and is eiit'ective to move the valve181 toward closed position on reduction of manifold suction. l/Vhen theengine is running relatively slowly and the throttle 100 is onlyslightly opened, the engine suction on the engine side of the valve 181is very high but at the same time this high suction is communicatedthrough the constantly open mixture passage to the anterior side of thevalve 181 so that i the force'which is actually effective to open thevalve is very slight and insuiiicient to overcome the resistance of thedash pot. As the throttle is opened the suction on the engine side ofsaid valve is reduced, but at the same time the suction between thevalve and the throttle is reduced more rapidly so that the forceeffective to open the valve is increased as the throttle opens and theengine speed increases and some predetermined engine speed becomessufficient to overcome the resistance of the dash pot and opens thevalve, the degree of opening depending on the pressure differentialbetween opposite sides of the valve. As the throttle is moved towardclosed position and this pressure differential becomes less, the spring187 is efiective to move the valve toward closed position and, finallyto completely close said valve.

The secondary mixing chambers comprise Venturi tubes 190 or other flowaccelerator elements. There are three of these Venturi tubes which areidentical in construction and are positioned in the branches 12, 14 and16 of the manifold 10, in such relation to the primary mixing tube,thatthepoint of greatest depression or suction in each Venturi tube isimmediately adjacent the outlet of the constantly open mixture passagewhich is associated therewith. Each venturi is provided with aprojecting rib 192 which fits when the manifold is attached to theengine block both in the engine intake port and in a recess 19st formedin the associated branch of the manifold, he rib engaging shoulders 196and 198 in the manifold and engine block respectively, when the deviceis assembled. The venturis produce a high suction at the ends of theconstantly opened mixture passages creating in tl passages a relativelyhigh suction and high velocity of flow therethrough. i

It will be noted that the mixture passages 76 slope downwardly from thenozzles to the point where they join the horizontal passages 118, sothat it will be impossible for liquid fuel to collect on the walls ofthese passages.

The above described device is operable, for reasons set forthhereinafter, to secure proper distribution of the fuel under allconditions of operation and provides a mixture of proper proportionsduring acceleration whenever the throttl is opened to accelerate,irrespective of the speed at which the engine is operating. At allengine speeds lower than that at which the valve 181 opens, all the iixture passes through the constantly open passages 118 and communicatingpipe connections to the intake ports. A such speeds these passages areof sufficient capacity to supply a large enough quantity of fuel tooperate the engine without loss in volumetric efliciency. Moreover, all.the air entering the carburetor is brought into contact with the fuel ina region of high suction, facilitating ese atomization and partialvaporization of the fuel; and also enabling satisfactory acceleration,since on opening of the throttle the resulting increased supply ofmixture is conveyed to the intake ports almost immediately and withoutdilution. Further, by the provision of a separate mixing chamber foreach intake port, from which the mixture is carried at high velocity toa point adjacent the port, collection of liquid fuel on the walls of themixture passages is prevented and equal distribution of the mixture issecured. This is substantially impossible with a carburetor having onemixing chamber supplying the mixture for all the intake ports throughone manifold, because of fuel collection on the walls of the manifoldand for other reasons.

it higher engine speeds the constantly open passages are of insufficientcapacity to supply enough mixture to meet the engine demands andadditional mixture must be supplied. It has been the practice heretoforein charge forming devices of this character, to open an air throttle ata predetermined speed to admit additional air to the secondary mixingchambers at such higher engine speeds to mix with the primary mixturetherein to supply the necessary quantity of mixture to the engine. Astructure of this character is fully disclosed in the copendingapplication previously referred to. The admission of this secondary airmakes it diflicult to secure satisfactory engine operation duringacceleration at all speeds above that at which the air throttle beginsto open because the secondary air, being much lighter than the primarymixture, reaches the secondary mixing chambers before the increasedquantity of fuel resulting from the opening of the throttle toaccelerate. This tends to lean the mixture temporarily, which causes theengine to miss with loss of power instead of the desired increase inpower.

According to the present invention, instead of admitting pure air to thesecondary mixing chambers at speeds above those at which the constantlyopen passages 118 and of sulficient capacity to supply enough mixture tomeet the engine demand, the valved passage 180 is opened, and themixture which passes the throttle is divided into two parts, the heavierportion comprising liquid fuel which is neither vaporized nor atomizedpassing through passages 118 and associated pipe connections and thelighter portion, comprising vaporized and atomized fuel, passing throughthe passage 180 and the manifold. This lighter portion of the mixturedoes not condense sufficiently on the walls of the manifold to interferematerially with equal distribution, while the unvaporized portion beingconveyed from three separate mixing chambers to points close to theintake ports, is also equally distributed to the various ylinders. Also,since that partof the mixure comprising vaporized and atomized fuel isproperly combustible, its admission to the secondary mixing chambers forremixtnre with the unvaporized fuel therein does not temporarily weakenthe mixture to present above described difficulty in acceleration.

In addition to the above described advantages of the present inventionin effecting superior distribution and acceleration, the structuredisclosed tends to form a more homogeneous mixture by separating themixture into its lighter and heavier portions and again mixing theseportions together.

Also the provision of the spring held valve the passage 180 maintains atall times a substantially constant suction in the secondary mixingchambers and, therefore, a substantially constant velocity of flowthrough the passages 118 and associated pipe connections. This suctionand flow velocity may be varied by usin springs of different force tocontrol the valve 184.

While the form of embodiment of the presentinvention as hereindisclosed, constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow.

What is claimee is as follows:

1. A charge forming device for internal combustion engines comprising amix' chamber, means for supplying fuel and a thereto, means effectiveunder certain operating conditions for separating said mixture into itsheavier and lighter constituents, separate means for conveying theheavier and lighter constituents of the mixture to a poi nt adjacent anengine intake port, means for remixing said heavier and lighterconstituents of the mixture, and means for preventing the separation ofthe mixture as described under certain operating conditions.

2. A charge forming device for internal combustion engines comprising amixing chamber, means for supplying fuel and air thereto, means forseparatingthe mixture into its heavier and lighter constituents,separate passages for conveying said heavier and lighter constituents ofthe mixture to the engine intake port and means in one of said passagesfor regulating the fiow therethrough.

3. A charge forming device for internal combustion engines comprising amixing chamber, means for supplying fuel and air thereto, means forseparating the mixture into its heavier and lighter constituents,separate passages for conveying said heavier and lighter constituents ofthe mixture to the engine intake port and means in the passage throughwhich the lighter portion of the mixture flows for regulating the flowtherethrough.

at. A charge forming device for internal combustion engines comprising amixin bers with one thereto, means for separating the mixture into itsheavier and lighter constituents, separate passages for conveying saidheavier and lighter constituents of the mixture to the engine intakeport and means normally closing the passage through which the lighterportion of the mixture flows, said means being adapted to open at higherengine speeds.

5. A charge forming device for internal combustion engines comprising amixing chamber, means for supplying fuel and air thereto, means forseparating the mixture into its heavier and lighter constituents,separate passages for conveying said heavier and lighter constituents ofthe mixture to the engine intake port and a suction operated valve inone of said passages for regulating the flow therethrough.

6. A charge forming device for internal combustion engines comprising amixing chamber, means for supplying fuel and air thereto, means forseparating the mixture into its heavier and lighter constituents,separate passages for conveying said heavier and lighter coi'istituentsof the mixture to the engine intake port, valve in the passage throughwhich the lighter portion of the mixture flows, and a spring holdingsaid valve closed at low engine speeds and adapted to permit opening ofthe valve by engine suction at higher engine speeds.

7. A charge forming device for a multicylinder internal combustionengine comp-rising a plurality of mixing chambers, means for supplyingfuel and air thereto, a plurality of separate mixture passages each ofwhich connects one of said mixing chambers with one of the engine intakeports, and asingle mixture passage connecting all of the mixing chamberswith said intake ports.

8. A charge forming device for a multicylinder internal combustionengine comprising a plurality of mixing chambers, means for supplyingfuel and air thereto, a plurality of separate mixture passages each ofwhich connects one of said mixing chamof the engine intake ports and asingle mixture passage connecting all of the mixing chambers with saidintake ports, and means controlling the flow through said passage.

9. Acharge forming device for a multicylinder internal combustion enginecomprising a plurality of mixing chambers, means for supplying fuel andair thereto, a. plurality of separate mixture conduits each of whichconnects one of said mixing chambers with one of the engine intakeports, said conduits being constantly open to permit flow therethroughat all times, a single mixture conduit connecting all of said mixingchambers with the engine intake port-s andmeans closing said conduit atlow enginespeeds but adapted to open at higher engine speeds. chamber,means for supplying fuel and air combustion engines comprising aplurality of mixing chambers, means for supplying fuel and air thereto,a throttle controlling the flow therefrom, a plurality of primarymixture passages adapted to convey all of. the. mixture to the engineintake ports at low speed, a. secondary mixture passage eifective athigher speeds and adapted to receive mixture from all of said mixingchambers, and means for regulating the flow through said secondarymixture passage.

11. A charge forming device for internal combustion engines comprising aplurality of mixing chambers, means for supplying fuel and air thereto,a throttle controlling the flow therefrom, a plurality of primarymixture passages adapted to convey all of the mixture to the engineintake ports at low speed, a secondary mixture passage effective athigher speeds and adapted to receive mixture from all of said mixingchambers, and an automatically'operated valve in said secondary mixturepassage to control the flow therethrough.

12. A charge forming device for internal combustion engines comprising aplurality of mixing chambers, means for supplying fuel and air thereto,a throttle controlling the flow therefrom, a plurality of primarymixture passages adapted to convey mixture from the several mixingchambers to the engine intake ports, and a secondary mixture passagecommunicating directly with all of the primary mixture passages, andeffective under certain operating conditions to convey a part of themixture to the said intake ports.

13. A charge forming device for internal combustion engines comprising aplurality of mixing chambers, means for supplying fuel and air thereto,a throttle controlling the flow -therefrom a aluralit of rimar mixturepassages, each of which communicates directly with one of said mixingchambers and is adapted to convey mixture to one of the engine intakeports, and a secondary mixture passage communicating with all the saidprimary mixture passages and conveying mixture therefrom to the saidintake ports under certain operating conditions.

14. A charge forming device for internal combustion engines comprising aplurality of mixing chambers, means for supplying fuel and air thereto,a throttle controlling the flow therefrom, a plurality of primarymixture passages, each of which communicates directly with one of saidmixing chambers and is adapted to convey mixture to one of the engineintake ports, a secondary mixture passage communicating with all saidprimary mixture passages to convey mixture therefrom to said intakeports under certain operating conditions, and a suction operated valvenormally closing the secondary mixture passage, but adapted to be openedat relatively high engine speeds to render said passage efiective. V

15. A charge forming device for internal combustion engines comprising aplurality of mixing chambers, a plurality of relatively small primarymixture passages conveying the mixture from said chambers to the engineintake ports, and a single relatively large secondary air passageadapted to be rendered efiective to convey the mixture from saidchambers to said intake ports under certain operating conditions.

16. A charge forming device for internal combustion engines comprising aplurality of mixing chambers, a plurality of relatively small primarymixture passages conveying the mixture from said chambers to the engineintake ports, a single relatively large secondary air passage forconveying the mixture from said mixing chambers to said intake portsunder certain operating conditions, and means for rendering the primaryand secondary mixture passages effective seriatim.

17. A charge forming device for internal combustion engines comprising aplurality of mixing chambers, a plurality of relatively small primarymixture passages for conveying all of the mixture to the engine intakeports at low engine speeds and a relatively large secondary mixturepassage which is rendered elfective at higher engine speeds to conveymixture to said intake ports whereby the velocity of the mixture ismaintained relatively high and substantially constant at all times.

In testimony whereof I hereto afiix my signature.

l/VILFORD H. TEETER.

